Don't forget about randomart used with ssh keys:
http://superuser.com/questions/22535/what-is-randomart-produced-by-ssh-keygensample:
Your identification has been saved in test.
Your public key has been saved in test.pub.
The key fingerprint is:
20:e9:b0:5b:5a:2b:ad:e8:4d:e4:b3:a0:32:49:2d:97 evan
The key's randomart image is:
+--[ RSA 2048]----+
| |
| . |
| . o . |
| + . . |
| o.= S |
| ooE . |
|.o*+o |
|=.+oo |
|=o.o |
+-----------------+